Protection Device of Oil-Smoke Sensor

ABSTRACT

A protection device for an oil-smoke sensor has a protection housing having two ends and an inner chamber; the first end having a first opening for receiving a probe of the oil-smoke sensor and in communication with the inner chamber; a second opening is disposed on the second end which is opposite to the first opening and in communication with the inner chamber. Because the probe is sealing mounted in the first opening, the probe will not be directly exposed in oil-smoke flow. The protective device is mounted such that the axial direction of the protective device is vertical to the oil-smoke flow direction. Therefore, the inner chamber of the protection housing has a pressure with respect to the oil-smoke flow that tangentially flows at a high speed, and the oil-smoke can only be diffused into the protection housing, thus, the probe is much less likely to be contaminated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.16/097,711, filed on Oct. 30, 2018, which is a national phase entranceof and claims benefit to PCT Application for a real-time fumeconcentration monitoring system and a range hood using the same,PCT/CN2017/000206, filed on Mar. 2, 2017, which claims benefit toChinese Patent Applications 201610398643.5, filed on Jun. 7, 2016. Thespecifications of the three applications are incorporated herein by thisreference.

FIELD OF THE INVENTION

The invention relates to the technical field of oil-smoke detection, inparticular to a protection device for an oil-smoke sensor.

DESCRIPTION OF THE PRIOR ART

Photoelectric sensors use photoelectric elements as detection elementsand operate in such a manner that changes of measured substances (suchas oil-smoke concentration) are converted into changes of opticalsignals, and then the optical signals are further converted intoelectric signals by the photoelectric elements. The photoelectricsensors are typically composed of a light source, an optical path and aphotoelectric element. As photoelectric detection methods have theadvantages of being high in precision, quick in response and free ofcontact and can detect various parameters and sensors are simple inmechanism and has flexible and various forms, the photoelectric sensorsare widely applied to detection and control.

In specific application scenes, components of the photoelectric sensorsmay be contaminated, which will result in sensitivity reduction and evenfailures. In certain scenes, the requirements for the collimation oflight paths and the capacity to resist natural light interference ofreceivers are high.

A Chinese Patent CN1900809A (Application No. 200510042977.0) disclosesan airflow-isolation camera lens dust-proof and dirt-proof protector,which is equipped with a clean compressed air source and aflow-adjustable conical ring-shaped airflow generator and can protectlenses by blocking dust with airflow. A Chinese Patent CN2837833Y(Application No. 200520132940.2) adopts a similar method by protectingphotoelectric oil-smoke concentration measurement devices with an aircurtain formed by high-pressure clean airflow, and thus, opticalelements are protected against contamination.

The above-mentioned protection device all have the following drawbacks;an additional clean air source is needed, clean air is difficult toprepared, and an additional power source is required to guide the cleanair into the devices.

SUMMARY OF THE INVENTION

A technical problem to be solved by the present invention is, in view ofthe prior art, to provide a protection device, which is simple indevice, low in cost and good in oil stain resistance, for an oil-smokesensor.

To solve the above technical problem, the protection device for anoil-smoke sensor comprises:

a protection housing having a first end, a second end, and an innerchamber;

the first end having a first opening for receiving a probe of theoil-smoke sensor and in communication with the inner chamber;

a second opening is disposed on the second end and in communication withthe inner chamber.

Preferably, the protection housing has a cylindrical shape, and theinner chamber in the protection housing also has a cylindrical shape.

As an improvement, an inner diameter of the inner chamber varies along alength of the inner chamber.

As an improvement, the inner diameter of the inner chamber incommunication with the first opening and the second opening issequentially decreased and increased N times, wherein N is a naturalnumber equal to or greater than 1. By decreasing and increasing theinner diameter of the inner chamber, a radial diffusion thrust isapplied to oil-smoke when the oil-smoke enters the inner chamber fromthe second opening, and most of the oil-smoke entering the tubular innerchamber is diluted in this section and adheres to the inner wall of thetubular inner chamber; and when the inner diameter of the inner chamberis decreased, another part of the oil-smoke is blocked by the wall inthe radial direction. After this process is repeated N times, it is muchless likely for oil-smoke to diffuse into the inner chamber to reach thesensor probe.

Preferably, N pairs of opposite baffles are disposed on the inner wallof the inner chamber in communication with the first opening and thesecond opening, and a gap is reserved between the baffles in each pair,N is a natural number equal to or greater than 1. By adoption of thismechanism, non-collimating light emitted by a transmitting probe of anoil-smoke sensor can be eliminated through N times of internalreflection, thus, ensuring the collimation of emergent light. As for areceiving probe of a sensor, the influences of natural light andenvironmental stray light on received signals can be greatly reduced.

Preferably, when N is greater than or equal to 2, the gaps between everytwo adjacent pairs of baffles are different.

Preferably, the center of the gap between each of the N pairs of bafflesis located on the same straight line with the centers of the firstopening and the second opening.

Preferably, N baffles are disposed in the inner chamber communicatedwith the first opening and the second opening, and each baffle isprovided with a through hole, wherein N is a natural number greater thanor equal to 1.

Preferably, when N is greater than or equal to 2, the through holes inevery two adjacent baffles have different diameters.

Preferably, central points of the through holes in the N baffles arelocated on the same straight line with central points of the firstopening and the second opening.

Preferably, the tubular wall of the protection housing has a variablethickness, so that the inner chamber communicated with the first openingand the second opening has a variable inner diameter.

Compared with the prior art, the present invention has the followingadvantages: an inner chamber communicated with the first opening and thesecond opening is formed in the protection housing, then the probe of aphotoelectric oil-smoke sensor is inserted into the first opening so asto be prevented from being directly exposed in an oil-smoke flow,oil-smoke can only be diffused into the protection housing, and thus,the probe is much less likely to be contaminated; and the protectiondevice has a good effect in preventing dust and oil-smoke pollution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a protection device for an oil-smokesensor according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view of the protection device for an oil-smokesensor according to Embodiment 2 of the present invention.

FIG. 3 is a sectional view of the protection device for an oil-smokesensor according to Embodiment 3 of the present invention.

FIG. 4 is a sectional view of the protection device for an oil-smokesensor according to Embodiment 4 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

To enable a further understanding of the present invention content ofthe invention herein, refer to the detailed description of the inventionand the accompanying drawings below:

Embodiment 1

FIG. 1 shows Embodiment 1 of the protection device for an oil-smokesensor of the present invention. As shown in FIG. 1, the protectiondevice comprises a tubular protection housing 1 which has a tubularinner chamber 2 inside the protection housing 1, a first end and asecond end. The first end of the protection housing 1 has a firstopening 3 in communication with the tubular inner chamber 2, and asecond opening 4 opposite to the first opening 3 is disposed on thesecond end of the protection housing 1 and in communication with theinner chamber 2. A probe 5 of the photoelectric oil-smoke sensor can beinserted into the first opening 3 in a sealed manner.

A baffle 6 is disposed in the middle of the tubular inner chamber 2 andis provided with a through hole. A central point of the through hole inthe baffle 6 is located on the same straight line with central points ofthe first opening 3 and the second opening 4.

According to this device, the deep inner chamber is designed to preventthe probe 5 of the photoelectric oil-smoke sensor from being directlyexposed in an oil-smoke flow; and the end, where the probe 5 isinstalled, is sealed, so that a positive pressure is formed in the innerchamber of the tubular protection housing 1 with respect to theoil-smoke flow tangentially flowing at a high speed, oil-smoke can onlybe naturally diffused into the tubular inner chamber, and thus, theprobe is less likely to be contaminated.

The design of the baffle 6 changes the inner diameter of the tubularinner chamber, so that when oil-smoke enters the inner chamber from thesecond opening 4, a radial diffusion thrust is applied to the oil-smoke,and thus, most of the oil-smoke entering the tubular inner chamber isdiluted in this section and adheres to the inner wall of the tubularinner chamber. As the inner chamber is blocked by the baffle 6, theoil-smoke further permeates into the inner chamber via the through holein the baffle 6, at this moment, another part of the oil-smoke isblocked by the wall of the baffle 6, and thus, it is much less likelyfor the oil-smoke diffused into the inner chamber to reach the sensorprobe 5.

Through this device, non-collimating light emitted by a transmittingprobe 5 can be reflected and eliminated when passing through theinterior of the baffle 6, thus, ensuring the collimation of emergentlight. As for a receiving probe 5, the influences of natural light andenvironmental stray light on received signals can be greatly reduced.

Embodiment 2

FIG. 2 shows Embodiment 2 of the protection device for an oil-smokesensor of the present invention. This embodiment differs from embodiment1 in the following features: a plurality of baffles 6 are disposed inthe tubular inner chamber in a spaced manner, and in this embodiment,the number of the baffles 6 is three; and through holes formed in everytwo adjacent baffles 6 may have identical diameters or differentdiameters, and in this embodiment, the through holes have identicaldiameters, as shown in FIG. 2. Through the multiple diameter-variablelabyrinth design, the inner diameter of the tubular inner chamber isincreased and decreased repeatedly. Every time the inner diameter of thetubular inner chamber is increased, a radial diffusion thrust is appliedto oil-smoke, so that most of the oil-smoke entering the tubular innerchamber is diluted in the corresponding section and adheres to the innerwall of the tubular inner chamber; every time the inner diameter of thetubular inner chamber is decreased, another part of the oil-smoke isblocked by the wall of the corresponding baffle; and this process isperformed repeatedly to make the oil-smoke entering the tubular innerchamber have a concentration gradient in the radial direction, and thus,it is much less likely for the oil-smoke diffused into the tubular innerchamber to reach the sensor probe. In addition, through thevariable-diameter design of the tubular inner chamber, an opticallabyrinth can be formed in the tubular inner chamber to eliminate light,with a large divergence angle, emitted by a transmitting probe, thus,ensuring the collimation of emergent light. As for a receiving probe,disturbance from natural light and environmental light can beeffectively reduced.

Embodiment 3

FIG. 3 shows Embodiment 3 of the protection mechanism for an oil-smokesensor of the present invention. As shown in FIG. 3, this embodimentdiffers from embodiment 1 in that, the tubular wall of the tubularprotection cover has a thickness gradually becoming smaller from themiddle to two sides, and thus, the tubular cavity has a variable innerdiameter.

Embodiment 4

FIG. 4 shows Embodiment 4 of the protection device for an oil-smokesensor of the present invention. As shown in FIG. 4, this embodimentdiffers from embodiment 3 in that, the tubular wall of the tubularprotection housing changes repeatedly, and thus, the inner diameter ofthe tubular inner chamber changes repeatedly.

Embodiment 5

FIG. 5 shows Embodiment 5 of the protection mechanism of an oil-smokesensor of the present invention. As shown in FIG. 5, this embodimentdiffers from embodiment 1 in the following features: one or more pairsof opposite baffles are disposed in the middle of the tubular innerchamber, a gap is reserved between the baffles in each pair, and centersof the gaps between the baffles are located on the same straight linewith centers of the first opening and the second opening.

1. A protection device for an oil-smoke sensor comprising: a protectionhousing having a first end, a second end, and an inner chamber; thefirst end having a first opening for receiving a probe of the oil-smokesensor and in communication with the inner chamber; a second opening isdisposed on the second end and in communication with the inner chamber;an inner diameter of the inner chamber varies along a length of theinner chamber; N baffles are disposed in the inner chamber communicatedwith the first opening and the second opening, and each baffle isprovided with a through hole, wherein N is a natural number greater thanor equal to 1; when N is greater than or equal to 2, the through holesin every two adjacent baffles have different diameters.
 2. Theprotection mechanism of claim 1, wherein the protection housing has acylindrical shape, and the inner chamber in the protection housing alsohas a cylindrical shape.
 3. The protection mechanism of claim 1, whereinthe inner diameter of the inner chamber in communication with the firstopening and the second opening is sequentially decreased and increased Ntimes, wherein N is a natural number equal to or greater than
 1. 4. Theprotection mechanism of claim 1, wherein N pairs of opposite baffles aredisposed on the inner wall of the inner chamber in communication withthe first opening and the second opening, and a gap is reserved betweenthe baffles in each pair, N is a natural number equal to or greaterthan
 1. 5. The protection mechanism of claim 4, wherein when N isgreater than or equal to 2, the gaps between every two adjacent pairs ofbaffles are different.
 6. The protection mechanism of claim 4, whereinthe center of the gap between each of the N pairs of baffles is locatedon the same straight line with the centers of the first opening and thesecond opening.
 7. The protection mechanism of claim 1, wherein centralpoints of the through holes in the N baffles are located on the samestraight line with central points of the first opening and the secondopening.
 8. The protection mechanism of claim 1, wherein the tubularwall of the protection housing has a variable thickness, so that theinner chamber communicated with the first opening and the second openinghas a variable inner diameter.